Flange bearing

ABSTRACT

An engine bearing for an internal combustion engine has a pair of separately constructed bearing halves comprising a pair of arcuate shells having a pair of laterally spaced flanges extending generally radially outwardly from each shell. Each pair of laterally spaced flanges comprises a pair of thrust faces facing generally away from one another with one of the thrust faces comprising an undulating contoured surface and the other thrust face having a generally planar non-contoured surface. The engine bearing is assembled having the contoured surface of one engine bearing half abutting the non-contoured surface of the other engine bearing half so that the engine bearing has generally opposite sides comprising both contoured and non-contoured surfaces.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates generally to engine bearings for internalcombustion engines, and more particularly to engine bearings havingradially outwardly extending flanges for accommodating thrust loads.

[0003] 2. Related Art

[0004] It is common to support internal combustion engine crankshaftswith journal bearings located at axially spaced locations along thecrankshaft. Each journal bearing typically includes a pair of matinghalves including an upper half bearing seated in an arcuate recess in alower part of an engine block, and a lower half bearing seated in anarcuate recess of a cap. The cap is typically bolted to the engine blockto retain the two bearing halves encircled about the crankshaft.

[0005] Of the journal bearings spaced along the crankshaft, typically,at least one journal bearing is designed to take an axial thrust loadapplied by the crankshaft. A crankshaft journal bearing capable ofwithstanding thrust loads in generally opposite axial directions isparticularly beneficial in pull-type diaphragm-spring clutchapplications. Pull-type diaphragm-spring clutches typically generate aforward acting thrust force while the clutch is engaged, and a rearwardacting thrust force while the clutch is disengaged. This results fromhaving the release bearing being pulled rearwardly in a pull-clutch,rather than being pushed forwardly as in a normal clutch application.Rearward thrust loads act on the crankshaft in normal diaphragm-springclutches, but they typically are not as high as the rearward thrustloads acting on the thrust bearings in pull-type diaphragm-springclutches. As such, it is even more beneficial that a crankshaft journalbearing be able to withstand bi-directional thrust loads in a pull-typeclutch application.

[0006] U.S. Pat. No. 5,192,136 discloses a journal bearing constructedwith a pair of generally opposite flanges on each bearing half havingoil grooves and contoured surfaces designed to seat against sidesurfaces of the crankshaft arms to take on bi-directional thrust loads.The contoured surfaces on each flange subdivide the thrust bearingsurface into a plurality of thrust pads. Each thrust pad is contoured togenerate a protective hydrodynamic wedge film thrust support action inorder to separate the two opposing surfaces and to preventmetal-to-metal contact between the thrust face and the crank shaft underaxial loading.

[0007] In manufacture, constructing each of the flanges of the journalbearing with oil grooves and contoured surfaces comes at a cost. Thenumber of manufacturing processes is increased, the amount ofmanufacturing time is increased, the amount of required tooling isincreased, potential scrap is increased, and the amount of labor isincreased, among other associated costs throughout the manufacturingprocess.

[0008] It is an object of the present invention to provide a suitablethrust bearing out of simpler construction and lower cost to overcomethe shortcomings of prior hydrodynamic thrust bearings.

SUMMARY OF THE INVENTION

[0009] A thrust bearing constructed according to the invention has apair of separately constructed bearing halves with an arcuate shellportions abutting one another about a longitudinal axis of the bearing.Each bearing half has a pair of longitudinally spaced flanges extendingradially outwardly from the shell and presenting longitudinallyoutwardly facing thrust faces. One of the thrust faces of each bearinghalf is contoured having hydrodynamic recessed features dividing thecontoured thrust face into a plurality of thrust pads and shaped toinduce a hydrodynamic flow of oil across the thrust face duringoperation of the bearing. The other thrust face of each bearing half issubstantially free of such hydrodynamic recessed features. According tothe invention, the contoured thrust face of one of the bearing halves isarranged on a longitudinally opposite side than that of the contouredthrust face of the other bearing half.

[0010] One advantage of the invention is that an inexpensive thrustbearing is provided having a bi-directional loading capabilities withonly one contoured thrust face on each bearing half arrangedlongitudinally opposite one another.

[0011] Another advantage of the invention is providing a split enginebearing requiring fewer manufacturing steps, namely eliminating theformation of a contoured surface on a thrust face of each bearing.

[0012] Another advantage of the invention is that the bearing halves maybe identical in construction but oriented with their contoured thrustsurfaces opposite one another to achieve bi-directional loading.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other features and advantages of the present inventionwill become more readily appreciated when considered in connection withthe following detailed description and appended drawings, wherein:

[0014]FIG. 1 is an exploded perspective view of a presently preferredembodiment of the invention;

[0015]FIG. 2 is a side elevation view of the assembled thrust bearing ofFIG. 1;

[0016]FIG. 3 is a cross-sectional view taken generally along lines 3-3of FIG. 2;

[0017]FIG. 4 is an enlarged and magnified partial view of the contouredthrust face; and

[0018]FIG. 5 is an alternate embodiment of the present invention.

DETAILED DESCRIPTION

[0019] A presently preferred embodiment of an engine thrust bearingconstructed according to the present invention is shown generally at 10in FIGS. 1-3. The engine bearing 10 is comprised of a pair of separatelyconstructed engine bearing halves 12, 14, wherein each half 12, 14 ispreferably identical to the other in construction. The engine bearinghalves 12, 14 have generally arcuate shells 16, 17 disposed in abuttingend-to-end engagement about a longitudinal axis 21 of the bearing 10,such that when the halves 12, 14 are assembled, the shells 16, 17 form agenerally cylindrical shell 19 defining an outer surface 18 and a boreor inner surface 20 of the engine bearing. Each half 12, 14 has a pairof longitudinally spaced thrust flanges 22, 24 extending radiallyoutwardly from each shell 16, 17.

[0020] The flange 22 of bearing half 12 has a contoured thrust face 26,while the opposite flange 24 of bearing half 12 has a generallynon-contoured thrust face 28. The other bearing half 14 has the samecontoured 26 and non-contoured 28 thrust faces, but which are arrangedlongitudinally opposite that of the thrust faces of the bearing half 12.As best shown in FIG. 4, the contoured faces 26 have a profilecomprising circumferentially spaced ramps 30 having low portions 32 andhigh portions 34. The ramps 30 are preferably arranged adjacent oneanother so that the low portion 32 of one ramp 30 is adjacent the highportion 34 of the adjacent ramp 30. Having the ramps 30 arranged in thismanner facilitates oil flow in the direction of shaft rotation, asrepresented in a counterclockwise direction by arrow R in FIG. 3.

[0021] By maintaining an oil flow across the contoured ramps 30 in thedirection of shaft rotation, a hydrodynamic oil film between the faces26, 28 and a mating surface, such as a shoulder on a crankshaft (notshown), is established and maintained. The oil film acts to inhibitmetal-to-metal contact between the flanges 22, 24 and the adjacentrotating surface of the crankshaft. To further facilitate the flow offluid, and thus the build-up of a hydrodynamic fluid film between ashoulder of a rotating crankshaft (not shown) and the thrust faces 26,28, cutouts 48 within the flanges 26, 28 may be formed at their ends tofeed oil between the faces 26, 28 and the crankshaft.

[0022] As best shown in FIG. 3, pressurized lubricating oil is suppliedto the bearing assembly through a hole or port in the cylinder blockwall (not shown) and into a groove 38 formed in the inner surface 20 ofeach shell 16, 17. As the crankshaft rotates in the direction of thearrow R, the oil is carried by the rotating shaft surface onto the innersurface 20 of the shell 17 of the lower bearing half 14. In thisfashion, a ring of oil encircles the shaft surface to providehydrodynamic radial support for the shaft. The inner surface 20 of thecylindrical shell 19 serves as a radial bearing surface for the shaft.

[0023] As best shown in FIGS. 1, 2 and 4, to further facilitate oil flowacross the contoured face 26, preferably a plurality of oil grooves 40are formed generally parallel to one another between each low portion 32and high portion 34 of the ramps 30. The oil grooves 40 facilitate theintroduction of oil between the contoured face 26 and a mating surfaceof the crankshaft. Once the oil is in the oil grooves 40, the oil ispreferably channeled circumferentially about the ramps 30 in thedirection of shaft rotation (R). It should be recognized that the oilgrooves 40 may be other than parallel.

[0024] In FIG. 5, like components and features of the embodiment ofFIGS. 1-4 are shown by the same reference numbers, but are offset by100. An engine bearing 110 having an axis of rotation 121 has flanges122 with contoured faces 126 comprising a plurality of adjacent ramps130. The ramps 130 have oil grooves 140 therebetween, with the oilgrooves 140 extending generally radially outwardly from the axis 120.

[0025] A recessed corner 50 is preferably formed where the flanges 22,24 meet the inner surface 20. The recessed corner 50 may be chamfered,flat, or rounded and is preferably sized to provide clearance with themating surface of the crankshaft. The clearance provides oil flowbetween the oil grooves 40, the contoured face 26, and the oil groove 38in the inner surface 20.

[0026] In use, the two bearing halves 12, 14 are brought together toform the cylindrical shell 19 (FIG. 2) so that the contoured face 26 ofeach half 12, 14 is aligned with the non-contoured face 28 of theopposite half 14. The journal bearing 10 thus has opposite sides 54, 56each with a contoured face 26 and a non-contoured 10 thus has oppositesides 54, 56 each with a contoured face 26 and a non-contoured face 28.Having only one flange 22 on each half 12, 14 with a contoured face 26results in a reduced number of manufacturing operations associated withthe manufacture of each half 12, 14. As such, the associatedmanufacturing costs is reduced for the journal bearing 10, 110.

[0027] Obviously, many modifications and variation of the presentinvention are possible in light of the above teachings. It is,therefore, to be understood that within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed. The invention is defined by the claims.

What is claimed is:
 1. A thrust bearing for use in journaling a rotatingshaft in a lubricated environment subject to thrust loading, said thrustbearing, comprising: first and second bearing halves having arcuateshell portions abutting one another about a longitudinal axis of saidbearing, and a pair of longitudinally spaced thrust flanges disposed oneach of said bearing halves and extending radially outwardly of saidshell portions and presenting longitudinally outwardly facing thrustfaces, one of said thrust faces of each of said bearing halvescomprising a contoured thrust face having hydrodynamic recessed featuresdriving said contoured thrust face into a plurality of spaced thrustpads and shaped to induce a hydrodynamic flow of lubricating oil acrosssaid contoured thrust face during operation of said bearing, and theother of said thrust faces of each of said bearing halves beingsubstantially free of such hydrodynamic recessed features; and whereinsaid contoured thrust face of said first bearing half is arranged on alongitudinally opposite side of said first bearing half than that ofsaid contoured thrust face of said second bearing half such that saidcontoured thrust faces face in longitudinally opposite directions. 2.The engine bearing of claim 1 wherein said contoured surface comprises aplurality of ramps having low portions and high portions adjacent oneanother.
 3. The engine bearing of claim 2 wherein oil grooves are formedbetween said low portions and said high portions of said ramps.
 4. Theengine bearing of claim 3 wherein said oil grooves are generallyparallel to one another.
 5. The engine bearing of claim 3 wherein saidoil grooves extend generally radially outwardly from said axis of saidbearing.
 6. A half engine bearing for an internal combustion engine,comprising: an arcuate shell having a pair of laterally spaced flangesextending generally radially outwardly from said shell and each of saidflanges having a thrust face facing generally axially outwardly fromsaid shell so that said thrust faces face generally away from oneanother with one of said thrust faces comprising an undulating contouredsurface and the other thrust face having a generally planarnon-contoured surface.